UNIVERSITY    OF   CALIFORNIA     AGRICULTURAL    EXPERIMENT    STATION 

COLLEGE    OF    AGRICULTURE  benj.  ide  wheeler,  president 

BFRKFI    py  THOMAS    forsyth    hunt,   Dean  and  Director 

CIRCULAR  Ncv-82^  ^> 


BOYS'  AND  GIRLS'  CLUB  CONTESTS,  NO.  2 
CLASS  A -FOR  BOYS 

POTATO  GROWING  CLUBS 

DEPARTMENT  OF  AGRICULTURAL  EDUCATION 


The  Object. — The  potato,  with  the  single  exception  of  rice,  is  the  most 
extensively  grown  food  plant  in  the  world.  There  is  not  a  county  in  Cali- 
fornia where  potatoes  cannot  be  grown,  and  it  is  the  object  of  this  circular 
to  encourage  boys  and  girls  to  enter  a  contest  to  see  who  can  produce  the 
largest  yield  of  potatoes  of  the  best  quality,  upon  a  given  area  of  land.  It 
is  possible  to  grow  over  600  bushels  per  acre,  yet  the  average  production 
throughout  the  United  States  is  only  about  90  bushels. 

Organization  Needed. — Boys  and  girls  in  each  school  should  form  a  potato 
growing  club  along  the  lines  suggested  in  Circular  No.  80,  a  copy  of  which 
will  be  sent  to  every  teacher  and  school  upon  request.  Address  The  Dean, 
College  of  Agriculture,  University  of  California,  Berkeley.  Elect  the  teacher, 
a  club  member,  or  somebody  interested  in  potato  growing,  as  the  president  or 
leader  of  the  club.  An  organization  with  a  definite  purpose  in  view,  i.e.,  the 
growing   of  potatoes,   is   necessary   for   a   successful   contest. 

Nature  of  the  Contest. — The  awards  will  be  given  to  the  boys  and  girls 
who  grow  the  largest  number  of  merchantable  potatoes  upon  a  given  area 
of  land,  and  who  select  the  three  highest  yielding  hills  of  marketable  potatoes 
from  their  patch  and  display  the  same  at  an  exhibition  or  fair  at  the  close 
of  the  contest.  All  the  tubers  from  each  selected  hill  should  be  saved,  the 
product  of  the  hills  being  kept  separate  in  paper  bags  or  boxes.  The  exhibit  may 
be  judged  by  means  of  a  score  card,  one  form  of  which  is  suggested  on  page  4. 
A  note  book,  describing  all  of  the  work  done  from  the  plowing  or  spading 
of  the  soil  to  the  harvesting  of  the  crop  (see  "How  the  Crop  was  Grown," 
blank  A,  page  4),  must  also  form  a  part  of  the  exhibit. 

Experimental  Plant  Growing. — Special  experiments  or  problems  have  been 
outlined  for  the  purpose  of  encouraging  boys  and  girls  to  study  the  science 
of  soils  and  of  crop  production.  The  problems  should  be  worked  out  in  the 
school  garden  whenever  possible  as  part  of  the  school  work  in  Agriculture, 
but  they  may  be  solved  at  home  when  land  at  school  is  not  available.  Out- 
lines of  these  problems  will  be  sent  to  all  teachers  who  request  them  and 
to  students  who  enroll  in  the  California  Junior  Experimental  League.  (Same 
address  as  for  Circular  No.  80.) 

When  to  Plant. — This  is  a  local  question,  dependent  upon  soil  and  climatic 
conditions,  and  which  must  be  determined  in  each  community.  The  planting 
of  the  main  crop  in  California  begins  in  January  on  the  light,  well-drained 
soils  of  Southern  California,  and  continues  throughout  February,  when  many  por- 
tions of  the  uplands  of  the  central  portion  of  the  State  are  ready.  During 
March,  April  and  May,  the  soils  of  the  upper  coast  valleys  and  the  mountain 


ranges  become  favorable  for  planting,  as  well  as  those  of  the  river  lowlands, 
which  are  drained  of  their  surplus  moisture.  A  general  rule  for  each  locality, 
would  be  to  plant  as  early  as  soil  and  climatic  conditions  will  favor  growth. 

Where  to  Plant. — Deep,  rich,  sandy  loams  are  the  best  for  potatoes,  as 
they  favor  root  development  and  growth  of  tubers  and  retain  sufficient 
moisture  to  produce  potatoes  of  quality.  However,  almost  any  kind  of  soil 
that  is  mellow,  warm  and  contains  the  requisite  plant  food,  will  produce 
good  crops.  Plant  on  an  alfalfa  sod,  if  possible,  but  ordinary  soil  enriched 
with  well-rotted  manure  the  fall  previous  to  planting,  will  do. 

Preparing  the  Seed  Bed. — If  an  old  alfalfa  soil  can  be  secured,  have  it 
plowed  or  spaded  during  the  fall  or  early  winter.  All  potato  soils  should  be 
made  mellow  to  a  good  depth  because  the  size  of  the  crop  depends  upon  an 
extensive  and  vigorous  root  system  and  this  in  turn  depends  upon  a  deep, 
mellow  seed  bed.  Give  the  potato  ground  at  least  two  plowing  or  spadings, 
the  first  turning  to  be  finished  before  the  winter  rains  begin.  Frequent 
harrowings  or  rakings  in  the  spring  up  to  planting  time  will  conserve  mois- 
ture, produce  good  tilth  and  keep  down  weeds. 

Choice  of  Varieties. — Many  potato  growers  have  not  standardized  their 
product,  that  is,  they  are  growing  several  different  varieties  in  the  same 
field.  The  highest  prices  are  paid  for  medium  sized  tubers  of  uniform  shape 
and  of  the  same  type. 

The  Early  Eose,  Early  Ohio  and  Bliss  Triumph,  are  suggested  for  Southern 
California.  The  Burbank  is  still  the  dependable  main  crop  potato,  although 
the  Snowflake,  Pearl  and  Peerless  are  worth  trying  in  many  sections.  Each 
club  should  find  out  what  variety  does  best  in  its  particular  locality,  and  then 
grow  that  and  no  other. 

Selection  of  Seed. — Seed  potatoes  should  not  be  smaller  than  a  hen's  egg, 
and  from  that  up  to  six  ounces  in  weight.  When  potatoes  are  cheap,  it  will 
usually  pay  to  plant  the  medium  size,  whole  tubers  as  they  favor  the  develop- 
ment of  vigorous,  heavy  producing  vines.  Seed  potatoes  should  be  smooth, 
and  of  a  type  that  the  market  demands,  because  of  the  tendency  for  the 
offspring  to  be  like  the  parent.  Eough,  gnarly  potatoes  are  not  apt  to 
produce  smooth  ones.  The  best  time  to  select  the  seed  potatoes  for  next 
year's  planting  is  when  this  year's  crop  is  being  dug.  Those  hills  having 
the  healthiest  and  most  vigorous  vines  and  producing  the  largest  number 
of  merchantable  tubers  of  uniform  size  and  shape,  should  be  reserved  for  seed. 

Treatment  for  Scab. — A  potato  disease  called  Scab,  which  causes  rough, 
warty  spots  on  the  tubers,  is  very  prevalent  in  this  State,  and  when  club 
members  find  their  seed  potatoes  to  be  affected,  they  should  treat  them  with 
a  fungicide.  Do  this  about  two  weeks  before  planting,  and  make  the  fungicide 
by  adding  one  ounce  of  formalin  (which  may  be  obtained  at  any  drug  store) 
to  each  two  gallons  of  water  used.  Place  the  uncut  seed  potatoes  in  a  bucket 
or  tub,  and  then  cover  them  with  the  diluted  formalin  solution.  Allow  the 
tubers  to  soak  for  two  hours,  then  spread  out  to  dry  and  leave  exposed  to 
the  light  (but  not  in  direct  sunlight)  until  planting  time.  They  will  turn 
more  or  less  green,  but  greening  is  good  for  them  as  it  hastens  germination 
and  will  make  the  young  plants  more  vigorous. 

Cutting  the  Seed. — Most  farmers  plant  only  the  small  (egg-sized)  tubers 
as  seed,  or,  when  using  the  larger  sized  seed,  cut  the  tubers  into  "two"  or 
"three  eye"  pieces.  The  approved  method  for  cutting  seed  potatoes  is  to 
halve  or  quarter  the  tubers  longitudinally.  Cut  from  the  eye  end  towards  the 
stem  end,  using  care  so  that  there  will  be  at  least  one  of  the  "seed  end" 
buds  on  each  piece.     Do  not  cut  the  tubers  until  ready  to  plant. 


Planting,  Depth  and  Distance  Apart. — The  depth  and  distance  apart  to 
plant  potatoes  depends  upon  soil  conditions  and  the  variety.  Other  things 
being  equal,  the  dryer  the  soil,  the  greater  the  depth,  and  the  richer  and 
mellower  the  soil,  the  closer  potatoes  can  be  planted  together.  Early  varieties 
may  be  planted  much  shallower  than  the  late  kind.  In  general,  the  seed 
should  not  be  planted  less  than  three,  nor  more  than  eight  inches  deep.  In 
good  potato  soil  the  hills  may  be  twelve  to  fifteen  inches  apart  in  the  rows, 
and  the  rows  two  to  three  feet  apart,  depending  upon  the  kind  of  cultivation 
used  and  whether  the  potatoes  are  irrigated  or  not.  The  amount  of  seed 
required  depends  upon  the  size  of  the  seed  piece  and  the  distance  of  planting. 
A  peck  to  100-foot  row,  or  8  to  10  bushels  per  acre  is  the  amount  usually 
required. 

Whether  the  seed  is  dropped  in  furrows  made  with  a  plow  or  hoe,  or  are 
planted  in  some  other  manner,  they  should  be  covered  as  soon  as  possible,  so 
as  to  be  surrounded  with  the  moist  earth.  Plant  in  straight  rows  to  make 
cultivation  and  irrigation  easier. 

Cultivation. — If  the  seed  bed  has  been  properly  prepared  and  the  crop 
properly  planted,  it  will  not  be  necessary  to  stir  the  ground  until  the  plants 
appear.  However,  if  a  crust  forms  after  planting,  it  should  be  broken  with 
the  harrow  or  rake.  As  soon  as  the  plants  are  up  so  that  the  rows  can  be 
seen,  given  them  a  good  cultivation  with  a  spike-toothed  harrow  or  a  garden 
rake,  the  kind  of  implement  used  depending  upon  the  size  of  the  plat. 

The  first  row  cultivation  should  be  done  with  a  small  shovel  cultivator 
when  the  plants  are  three  to  six  inches  high,  breaking  up  the  middle  of  the 
rows  to  a  depth  of  four  to  6  inches.  All  later  cultivation  should  be  done  with 
a  spike-tooth  cultivator  or  a  hand  rake,  and  the  cultivator  teeth  should  not 
penetrate  to  a  depth  of  over  three  inches.  Flat  cultivation  is  the  general 
practice,  excepting  when  it  is  necessary  to  make  a  furrow  or  depression  be- 
tween the  rows  in  order  to  irrigate.  In  the  Lompoc  or  Salinas  districts  in 
this  State,  however,  the  growers  have  found  it  necessary  to  ridge  the  potato 
rows,  so  contestants  must  be  guided  by  the  general  practice  in  their  neighbor- 
hood as  to  whether  they  will  practice  ridge  of  flat  culture.  Good  cultivation 
will  maintain  a  dust  mulch  throughout  the  season,  thus  preserving  the  mois- 
ture and  not  permitting  weeds  to  grow. 

Irrigation. — The  time  to  apply  water  and  the  amount  to  use  varies  with 
the  soil  and  the  season.  A  general  rule  must  suffice  here.  Irrigation  water 
should  be  applied  only  when  the  condition  of  the  plants  indicates  that  they 
need  moisture.  The  rather  sudden  darkening  of  the  foliage  is  a  reliable 
indication  of  the  need  of  moisture.  Or,  one  may  dig  into  the  soil  between 
the  hills  and  try  to  make  a  ball  out  of  a  handful  of  earth;  if  it  fails  to 
retain  its  form,  irrigation  is  needed.  Try  to  carry  the  vines  through  the 
blossoming  period,  if  possible,  without  irrigation.  The  general  rule  will  be, 
however,  to  irrigate  when  moisture  is  needed  by  the  plant,  regardless  of 
everything  else. 

Irrigate  the  first  time  by  running  the  water  between  alternate  rows.  Let 
the  water  run  in  the  rows  until  it  has  seeped  through  and  moistened  the 
middles  of  the  non-irrigated  rows.  This  is  a  sign  that  enough  water  has  been 
applied.  Try  to  apply  the  water  in  deep,  narrow  furrows  in  the  middle  of 
the  rows  so  that  the  soil  immediately  surrounding  the  tubers  will  be  mois- 
tened by  capillary  water  rather  than  being  made  wet  with  percolating  water. 
At  the  second  irrigation  run  the  water  down  the  rows  that  were  not  irri- 
gated the  first  time,  and  so  on  throughout  the  season,  if  more  applications  are 
needed.      Cultivate   as   soon   as   possible   after   each   irrigation    so   as   to    check 


evaporation  and  prevent  the  ground  from  baking.  Refrain  from  irrigation 
for  at  least  twenty  to  thirty  days  before  digging  time,  so  that  the  tubers  can 
ripen  in  a  fairly  dry  soil.  Give  potatoes  just  enough  water  to  keep  healthy 
and  vigorous,  but  do  not  over-irrigate.  Too  much  water  rather  than  too 
little,  is  being  used  by  most  potato  growers  when  irrigation  is  practiced. 

Harvesting. — Potatoes  are  usually  dug  with  a  machine  potato  digger,  but 
probably  all  of  the  club  members  will  have  to  "lift"  their  crop  by  hand 
with  a  potato  hook  or  fork.  Dig  each  hill  carefully  and  keep  the  tubers 
separate  from  those  of  all  other  hills  so  that  the  three  best  hills  can  be  more 
readily  selected.  Keep  the  product  of  these  selected  hills  in  a  cool,  dark  place 
until  the  fair  or  exhibition  time.  Sack  up  the  remaining  hills  in  the  usual 
way,  weigh  the  entire  product  and  store  in  a  suitable  place  until  they  are 
sold  or  used. 

SUGGESTED   SCORE    CARD   FOR   POTATO    GROWING    CONTESTS. 

Value.     Score. 
Largest   authenticated   yield    (from    a   given    area    or   number 

of  hills) 25 

Note  book  (for  neatness,  accuracy  and  completeness) 25 

Potato  Exhibit  (all  the  tubers  in  the  three  best  hills  must  be 
exhibited  and  will  constitute  one  entry;  the  tubers  from 
each  hill  should  be  kept  separate  and  be  displayed  sepa- 
rately)      50 

Uniformity  and  appearance  of  exhibit 10 

Trueness  to  type  (characteristics  of  the  variety) 10 

Table  value,  judged  on  the  following  points: 30 

Shape 5      (Round  or  oval  shape  preferred.) 

Size 5      (Medium  size,  rather  than  very  large.) 

Eyes 5      (Medium  depth,  well  defined  and  not 

too  numerous.) 

Skin 5      (Thick,  fairly  tough  skin,  free   from 

blemishes.) 

Texture 5      (A    fine    grained,    brittle    texture    is 

preferred.) 

Soundness 5      (Sound  and  firm;  test  for  hollowness 

and   texture   by   cutting   open   the 
three  largest  tubers.) 

Total,  a   possible 100 

How  the  Crop  was  Grown. 

Note  books  should  give  full  information  concerning  each  of  the  following  points: 

1.  Name  of  contestant;  address;  school  attended. 

2.  Area  of  plot  in  square  rods  or  total  length  of  rows;  number  of  hills  planted. 

3.  Kind  of  soil:  Sand,  clay,  loam,  adobe,  humus,  peat. 

4.  Kind  of  crop  grown  on  plot  year  before. 

5.  Kind,  amount  and  value  of  fertilizer  used. 

6.  Preparation  of  soil;  date  and  depth  of  each  plowing,  spading,  harrowing, 

raking,  etc. 

7.  Variety  planted. 

8.  Where  seed  was  obtained. 

9.  Amount  of  seed  required. 

10.  Describe  treatment  of  seed  for  scab. 

11.  Method  of  " greening"  and  cutting  seed. 

12.  Date  and  method  of  planting. 

13.  Date  when  vines  came  up  and  when  in  full  bloom. 

14.  Dates  and  manner  of  irrigating. 

15.  Dates  and  method  of  cultivation. 

16.  Date  of  harvesting. 

17.  Yield  of  plot  in  pounds. 


